1. Field of the Invention
The present invention relates to a leathered steering wheel for steering a vehicle, and in particular, to a leathered steering wheel in which the outer circumference is covered with a leather layer in a ring part.
2. Related Art
Conventionally, as shown in Japanese Patent Publication No. 2000-43736A, there is a leathered steering wheel of a structure of an outer circumference of the ring part covered with the leather layer allover. In this kind of steering wheels, a core of the ring part is arranged on the circumference of the wheel. And the core is covered with a covered layer of a soft synthetic resin, and the leather layer is placed to cover the outer circumference of the covered layer.
In the leathered steering wheel of such a structure, the leather layer is formed by combining a plurality of divided end portions of the leather materials each other in a manner that the outer circumferential face of the ring part is covered neatly. When the leather layer has such a structure, in view of appearance of the steering wheel, tactile feel at use, or abrasion resistance, the leather materials should be joined without forming unevenness at the joint portion.
Therefore, as the leather layer 1, one of the related art shows thin portions 2d by thinning obliquely back sides of the leather materials 2, 2 as seen in FIG. 1A, in a manner that end portions 2b to be connecting sides become thinner respectively in thickness as going to end sides 2c in main portions 2a, 2a of neighboring leather materials 2, 2, and the related art stitches the leather materials 2, 2 each other at almost centers of the thin parts 2d as seen in FIG. 1B. In the leather layer 1, as seen in FIG. 1C, adhesive layers 4 are coated on the back sides of the thin portions 2d, and portions 2e at the front end of stitched portion 3 are turned down respectively and adhered to the respective leather materials 2, such that the end sides 2c are returned to initial sides. At this time, the thin portions 2d at the end portions 2b of the leather material 2 are set so that, when turning down the ends 2c, the turned portions 2e do not protrude the surface of the leather materials 2.
However, even if the leather layer 1 is composed as mentioned above, the thickness around the stitching portion 3 is larger than that of the main portion 2a of the leather material 2, and if the leather layer 1 is placed on the outer circumference of the covered layer 5, as shown in FIG. 1D, the part about the stitching portion 3 largely and inevitably protrude. Therefore, using for a long time, the parts about the stitching portion 3 are worn.
Further, in other related art, as shown in FIG. 2, a predetermined position of the covered layer 8 is defined with a groove portion 8a, into which the leather materials 7 coated with the adhesive agent are fitted at ends 7a to combine the ends 7a each other, thereby arranging the leather layer 6 so as to cover the outer circumference of the covered layer 8.
However, in case the leather layer 6 is so structured, the groove portion 8a is necessarily defined in the covered layer 8 for fitting the ends 7a of the leather materials 7, and therefore, when changing the positions of combining the leather materials 7 in the ring part, designing alterations as a metal mold are accordingly necessary for forming the covered layer 8, and countermeasures therefore are not easy.